# from multiprocessing import Process
# import os

# # 子进程要执行的代码
# def run_proc(name):
#     print('Run child process %s (%s)...' % (name, os.getpid()))

# if __name__=='__main__':
#     print('Parent process %s.' % os.getpid())
#     p = Process(target=run_proc, args=('test',))
#     print('Child process will start.')
#     p.start()
#     p.join()
#     print('Child process end.')




from multiprocessing import Pool
import os, time, random

def long_time_task(name):
    print('Run task %s (%s)...' % (name, os.getpid()))
    start = time.time()
    time.sleep(random.random() * 3)
    end = time.time()
    print('Task %s runs %0.2f seconds.' % (name, (end - start)))

if __name__=='__main__':
    print('Parent process %s.' % os.getpid())
    p = Pool(8)
    for i in range(100):
        p.apply_async(long_time_task, args=(i,))

    print('Waiting for all subprocesses done...')
    p.close()
    p.join()
    print('All subprocesses done.')



